Automatic disengaging device for the knife-gear of mowing-machines.



No. 821,612. PATENTED MAY 29, 1906. C DAHL & C. LUND.

AUTOMATIC DISENGAGING DEVICE FOR THE KNIFE GEAR OF MOWINC MACHINES.

APPLICATION FILED OCT.31,1904.

2 SHEETS-SHEET 1.

c7%; v a/1' No. 821,612. PATENTED MAY 29, I906.

- 0 DAHL & 0. LUND.

G DEVICE FOR THE KNIFE GEAR-0F MOWING A UTOMATIO DISENGAGIN MACHINES.

APPLIOATION FILED 002:. 31, 1904.

2 SHEETSSHEET 2 UNITED STATES CHRISTI AN DAHL, OF

PATENT TTTbn.

AUTOMATIC DISENGAGING DEVICE FOR THE KNIFE-GEAR OF MOWING-MACHINES.

Specification of Letters Patent.

Patented May 29, 1906.,

Application filed October 31, 1904- Serial No. 230,728.

To coZZ whom it may concern:

Be "it known that we, CHRISTIAN DAHL, a resident of Gross Nustrup, and CHRISTIAN LUND, a resident of Porsgeil, Germany, subjects of the German Emperor, have invented certain new and useful Improvements in Automatic Disengaging Devices for the Knife- Gear of Mowing-Machines, of which the following is a specification.

The present invention relates to an automatic disengaging device for the knife-gear of mowing-machines, which begins to work as soon as a hard object has been introduced between the knives and would injure them.

It is not new to make the operating-rod of the knives yielding so that the knives are stopped by stones, &c., and are not completely destroyed, owing to the yielding connecting-rod, although the crank continues working; but it is obvious that in this case the operating-rod gives a continuous reciprocating motion to the knives and presses them with a certain variable force against the hard object, so that notches are produced in the cutting edges of the knives.

According to the present invention the whole driving mechanism is automatically stopped as soon as the knives are stopped. All mowing-machines are provided with a disengaging mechanism which does not Work automatically and needs to be'operated by hand.

The object of the present invention is to render automatic the disconnecting device,

, which hitherto was operated by the driver.

In the annexed drawings, Figure 1 shows a perspective view of a mowing-machine con structed according to the present invention, all parts not appertaining to the invention being omitted. Fig. 2 is a front elevation of the device, partly in section. Fig. 3 is a plan view of same. Figs. 4 and 5 are front elevations like Fig. 2 of the device, but disconnected and in two different working positions.

The disconnecting device com rises a single-armed lever Z, which is loose y mounted between two collars l and 2 upon the rotating axle. Upon the hub of this lever Z is keyed at a right angle an arm 1', the opposite end of which engages the oblique slot 8 of the hub of the large conical wheel 0, so that the lever Z must rotate with the wheel 0. As the large wheel 0 is slidably mounted upon the axle by means of a flat key, it is obvious that when lever Z is stopped the wheel is laterally shifted by the arm '1", sliding along the oblique slot 3, Figs. 4 and 5. The wheel 0 therefore no longer engages the small wheel p, so that the knives are disengaged as the rotation of the shaft q ceases. The disengaging is automatically effected in the following manner: The knife-carrier a is not directly engaged by the actuating-rod Z. The latter engages a relatively strong spring 0, secured to the knife-carrier a. A system of levers d is pivotally connected to the machine-framework in two points e and is terminated at each end by a fork. The prongs f and g of the lefthand fork are at different levels, so that the operating-rod Z) during its reciprocating motion passes freely over the prong f and under the prong g. When the knife carrier is stopped by a stone, the spring 0 is forced to bend and its right side is lowered when the connecting-rod b is moving toward the knives. It touches thus the prong f and pushes it to one side, Fig. 5. By the intermediary of the levers (Zthe pronghof the right side fork engages between two teeth of a toothed wheel 7c, mounted freely upon the hub, Fig. 5. This wheel is thus stopped, as well as the disengaging-lever Z, the wheel Zr and the lever Z being connected together by a U-shaped spring m. When the wheel and the lever Z have been stopped by the prong h until the arm 1* has reac ed the end of the slot s-that is to say, When the wheel ois disengaged (see Figs. 4 and 5)-the spring m under the increasing pressure leaves the lever Z. The wheel Zc is held stationary by the prong h while the lever Z rotates. This rotation does not produce the Working of the knife, the wheel 0 remaining disengaged. The hard object is removed from between the knives. The wheel 0 is again coupled by hand with the aid of the lever Z. The U-shaped spring m of wheel la is again placed upon the lever Z, and the mechanism is again in working condition, as shown in Fig. 2. The parts are evidently arranged in such a way that the lever Z when rotating does not meet the fork h. If the knife-carrier is stopped when the driving-rod is movmg toward the opposite side, the spring 0 is stretched, so that its right part is raised and a peg a, fixed upon the connecting-rod Z), engages the longer prong g and pushes it to one side. The other prong of the fork h is thus caused to engage the teeth of wheel 7c, Fig. 4, and like effects are obtained as in the abovedescribed case.

Having now fully described our said invention, What We claim, and desire to secure by Letters Patent, is-

In a device for disengaging the knife-gear in mowing-machines, the combination With the knife-carrier a and the actuating-rod Z, a bent spring 0 connecting the knife-carrier a to the actuating-rod b and allowing of the latter moving When the knife-carrier is accidentally stopped, a peg 7L provided on the upper side of the actuating-rod near its connection With the bent spring 0, a fork f, 9 one prong f whereof is adapted to be engaged and actuated by one end of the said bent spring, While the other prong g is adapted to be engaged and actuated by the said peg n, a system of levers (1 adapted to communicate the motion of the fork f, g to another fork h, a toothed r, substantially as and for the purpose set forth.

In testimony whereof We have hereunto set our hands in presence of tWo Witnesses.

CHRISTIAN DAHL. CHRISTIAN LUND.

Witnesses:

CHR. N IssEN, MATH. KooxY and engaged by the free end of the said arm 

